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Trimmer dead zone

Trimmer dead zone

2014-06-12 by ipc.de@...

Hey,
�
There is no trimmer for the dead zone. You need to include one or two more diodes in series to each of the original "dead band" diodes on the mod-board. I don't have the schematics available right now, but that is the way to want to go.
�
I will post a picture of the respective section in the circuit soon, if you like.
�
Best
Mondo

Re: Trimmer dead zone

2014-06-12 by walter bonacci

Actually I'm wondering if the problem is not the pot, I can hear slight variation in pitch even when moving the lever to a certain angle keeping it steady.
Is it complicate to clean up the pot? Do you guys have an idea of how long does it take? I'm right now trying to figure out how to detach the electronic part from the bottom of the modulation block.

Thanks.
W.

Re: [oberheim] Re: Trimmer dead zone

2014-06-12 by Patrick Edwards

You can always replace it. It isn't very fun to remove the mechanism and recenter the pot for 0v but it is well worth it to put in a new one. I always replace them (Mouser no. 31VC401-F) and it stops jumping around, actually has a small dead band, and helps autotune actually work. The Oberheims don't disconnect the pitch lever when autotuning so if there is any instability it craps out.
Show quoted textHide quoted text
On Thu, Jun 12, 2014 at 5:51 AM, walter bonacci walterbonacci@... [oberheim] <oberheim@yahoogroups.com> wrote:

Actually I'm wondering if the problem is not the pot, I can hear slight variation in pitch even when moving the lever to a certain angle keeping it steady.
Is it complicate to clean up the pot? Do you guys have an idea of how long does it take? I'm right now trying to figure out how to detach the electronic part from the bottom of the modulation block.

Thanks.
W.




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Re: Trimmer dead zone Pitchbenb OB-Xa

2014-06-13 by ipc.de@...

Hi,

I never succeeded in cleaning the original bend pots. It might help a
little, but surely doesn't solve your dead band problem.
As posted by others, a stable dead band is VERY essential for a correct
OB-Xa tuning.
If you don't want to replace the pot with a new one (special type), try to
include the diodes which IMHO is easier to do than the pot replacement,
provided you are handy with the solder gun (grab it on the right end...)

Good Luck

Mondo

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